The manufacturing process for virtually every industry has evolved to some level of automation. Computers and computer-controlled machinery now control and monitor almost every aspect of the manufacturing and industrial process. The management of this automation involves elaborate and detailed software platforms targeted to perform industrial or process control. Most companies within the industrial controls market use software referred to as Human Machine Interface (HMI) software. HMI is a generic term describing any software package used to interface process control information with a human operators.
In its basic elements, HMI systems communicate with field controllers and bring data from those controllers into a central database for processing and monitoring. An operator in a single location can then monitor and control the industrial process throughout a facility. HMI systems, therefore, centralize the management and collection of data from field control devices into one location.
Field controller devices are connected to a process control system over a communication network and typically comprise programmable logic controllers (PLCs), which are programmable computing devices used to monitor elements or conditions in plant or machine operation such as temperature, pressure, number of cycles, etc. The PLC itself may comprise a small box with several computer controlled instruments or may comprise a self-contained microcontroller system. A PLC xe2x80x9cboxxe2x80x9d may comprise an oscilloscope functionality, a computer controlled valve, or a simple environmental sensor, such as a thermometer or barometer. PLCs may also generally be used to control various tasks in the overall manufacturing or industrial process such as stopping or starting the flow of material or electricity, diverting flow, or any other such activity. In order to properly manage process control information, HMI systems generally need to have the process control data, which is gathered by the PLCs, transported to the central location of the HMI server. Until recently, much of the process control data was transported over proprietary networks. These are networks provided by field controller manufacturers which supply the PLCs, the network devices, the cabling, the process servers, and the communication format.
Because each proprietary network uses its own communication formats and protocols, manufacturing and industrial facilities are restricted to purchasing all compatible equipment solely from the proprietary network manufacturer. This closed network restriction typically requires the customer to have all software customized to the particular network protocols used by the network manufacturers. Customers also typically maintain programming personnel to develop new device drivers in the proprietary formats in order to maintain compatibility with new equipment or new processes. Without such programming personnel, a customer would have to pay the network manufacturer to develop customer-specific device drivers. Such closed formats cause industrial and manufacturing customers to expend a great deal of money to maintain the network.
Recently, the process controls industry has begun evolving into the use of open architecture networks. One such open architecture network that is beginning to find applications in the process controls industry is Ethernet. Through its business applications, Ethernet has become one of the most popular types of local area networks (LAN) for business or office computer systems. Ethernet is based on carrier sense multiple access/collision detection technology (CSMA/CD). Ethernet devices such as hubs or switches control the data transfer over the network by sensing whether the network is currently in use. If no use is detected, data is allowed to flow through the system. If the system is occupied, the data transfer is held until the system is free. Network devices also detect collisions, which are events caused when two devices attempt to transfer data over the network at the same time. Through this series of collision detection and use sensing, along with priority algorithms for managing collisions, data is quickly and efficiently transmitted between network devices.
One of the main benefits of Ethernet networks for business systems came with the development of 10 Base-T Ethernet technology. The 10 Base-T technology allowed the Ethernet network and information to be transmitted over the regular twisted pair wiring found in most telephone systems. This enables Ethernet networks and LANs to be installed in buildings using the twisted pair wiring already installed for the telephone network. While Ethernet networks may also be constructed with coaxial cable or fiber-optic cable, the twisted pair capability has allowed Ethernet to rise to the level of an industry-standard in office LAN technology.
The data transmission in an Ethernet network derives from the series of network devices such as hubs, switches, and routers. Ethernet hubs are centralized switching units that connect to all of the nodes on the network. Every node connected to the hub transmits its status information to the hub in a standard format, such as simple network management protocol (SNMP). After receiving this information, the hub rebroadcasts it, in SNMP, out to all of the other nodes connected to the hub. In this manner, each device is able to monitor the status and activity of each other device connected to the hub.
While Ethernet grew into an effective business/office LAN standard, the same Ethernet devices could not readily be transported into an industrial controls network. The typically hostile environment on the manufacturing plant floor provides elements, such as extreme temperatures, electrical interference, and continuous vibration, which are generally and desirably not present in an office environment. Ethernet network devices, which were robust enough for the office LAN, would typically experience short life cycles and unreliable performance when exposed to the harsh industrial environment. However, as the industry began recognizing the benefits of the Ethernet standard, companies slowly developed new robust Ethernet devices designed with increased environmental shielding. Thus, the process controls industry began assembling plant and industrial networks using Ethernet technology. Ethernet-based HMI systems and field logic controllers have since been developed for the growing number of process control systems implemented over Ethernet networks. The influx of more suitable Ethernet equipment and compatible software has caused an industry shift toward open architecture networking systems and standardization.
The new Ethernet HMIs basically perform the same function of interfacing the data gathered by the field logic controllers with the human technician. However, with the shift toward open networking, new standardized formats have been developed for communicating process control information within HMI platforms. Based on Microsoft Corporation""s OLE technology, a standard called OLE for Process Control (OPC) is being incorporated into more HMI platforms. Working inside of the HMI platform, OPC standardizes the communication of process data obtained from field controllers. While the PLC vendor may still have a proprietary transport protocol, once the information is passed through a system interface, the HMI platform can universally process and internally communicate the data through OPC. In this manner, the HMI system is able to process the information independently from the PLC vendor protocol.
In some industrial applications, excessive pressure or temperature could lead to a catastrophic event causing serious loss of life and/or environmental contamination. These industries in particular have a critical need to monitor the real-time network status to ensure that the real-time process control data received by the HMI system is accurate. Because Ethernet technology became a standard for office LAN systems, many network management software systems exist which monitor network status and performance. Industrial users are thus able to purchase such network management software to monitor their network status. However, process control is critical to many industrial users. Network management software is typically run from a separate server or computer system and generally is monitored from a separate work station.
Because the network management software solutions currently available for industrial users is the same software used by regular businesses and corporations, the tolerance level for program stability and average time between failures is not as stringent. The office or corporate environment does not typically require a high tolerance for program stability. Most industrial users are not willing to risk process control failure by running such a separate network management software with their HMI systems on the same platform. Therefore, industrial Ethernet networks typically have one computer system running the process control HMI platform and a second computer system running the network management software.
An obvious disadvantage to the current state of the art is the dual computer systems generally required. The two systems increase the expense and complexity of the industrial network. One workstation is typically required to monitor process control information while another separate workstation, under control of an entirely separate server, is generally required to monitor the condition of the network.
Furthermore, because the Ethernet standard was developed outside of the process control industry, the communication protocol for network information, SNMP, is incompatible with process control data protocol, OPC. Therefore, the existing Ethernet HMI platforms cannot process or receive the network condition information sent by the network devices.
The only existing way to monitor both network status and process control is through use of some of the proprietary networks. The proprietary networks would typically use a single protocol to communicate all information. However, a major disadvantage of the proprietary networks is the closed network architecture. A proprietary network owner must purchase all equipment and software from the manufacturer. Non-proprietary equipment or software will be incompatible, thus, severely limiting the scalability and flexibility of the network.
In consideration of the disadvantages inherent in the current state of the art, it would be advantageous to have an HMI platform capable of simultaneously monitoring both network status information and process control data in the same HMI platform and using an open architecture network. These and other features and technical advantages are achieved by a system and method that incorporates a process control data interface and a network data interface into a singular HMI platform, wherein the network data interface converts the network protocol of the open architecture network into the process control protocol for use by the HMI system.
A preferred embodiment of the present invention establishes a system for integrating management of process and network data. It includes a user interface for displaying the process and network data to a user. The inventive HMI platform incorporates a process data interface, in communication with a process interface, for receiving process data gathered by at least one programmable device on a network and at least one network data interface, for receiving network data from a network device. The network data interface receives the network data communicated to the network data interface using a first protocol, such as SNMP or Remote Monitoring (RMON). The inventive system also includes a process server, which is in communication with the user interface, the process data interface, and the network data interface. The process data interface communicates process data to the process server in a second protocol, such as OPC, which preferably has both synchronous and asynchronous transfer ability. The network data interface preferably communicates the network data to the process server in the second protocol by advantageously converting the network data from the first protocol into the second protocol. The process server selectively manipulates both the process data and the network data responsive to a set of application rules and communicates the resulting process and network data to the user interface for display.
The inventive system preferably performs the management integration through a method for managing process control information in a process application implemented with at least one programmable computing unit connected through an open network system. The preferred embodiment method comprises providing process control information to a process information interface, wherein the process control information is gathered by the programmable computing units. The system also preferably provides network status information from at least one network device to a network information interface using a network management protocol, such as SNMP or RMON. The system preferably communicates the process control information to a process control server using a process control protocol, such as OPC. The network status information is preferably translated from the network management protocol into the process control protocol and communicated to the process control server. The process control server compiles the process control information and the translated network status information according to application criteria and then selectively displays the compiled process control information and translated network status information to a user.
A user may also manage and control the network operations through the network devices by issuing network commands delivered through the network information interface. The collection of network information will preferably be suspended while the control commands are sent through network information interface. Therefore, a user may turn on, turn off, redirect, etc., the network devices through the same HMI system from which he/she monitors and controls the process control. Similarly, a user may manage the process control by issuing process commands to the PLCs connected to the network.
The translation is preferably implemented by creating a runtime database that stores all of the retrieved network information after it has been stripped of all control codes generally required by the network management protocol. The network information is then preferably retrieved by a process server interface, which appends the transport codes appropriate to the process control protocol. The translated network information is then communicated to the process server for ultimate presentation to the user.
Depending on the industry or particular needs of the network, the process control and network status data will typically be monitored and/or controlled in real-time. The inventive system allows for configuration to monitor real-time or any other time constraint desired by the user. A preferred embodiment of the present invention also preferably allows configuring the system with additional memory for storing both the process control data and the network condition information. A preferred embodiment would preferably include a chronological memory dedicated to storing the chronological progression of process and network data. Therefore, by accessing this memory a user could track both process control and network status data to observe plant conditions in previous days or hours. A preferred embodiment also preferably includes a parameterized memory dedicated to storing selected process control and network status information. A user could preferably set alarm conditions or limits, such as if a temperature gets too high, or pressure gets too low, or any number of difference conditions. If the real-time data shows any value exceeding these limits, the HMI process server preferably records and stores the process control data along with the corresponding network status information into the parameterized memory. The HMI platform would also typically include other alarms or indicators to draw attention to the alarm condition depending on the volatility of the process state. In addition to setting limits on process data, the user could also specify network data limits such as number of collisions per hour, etc. The network status data would similarly be stored in the parameterized memory along with the corresponding process control data. Therefore, by including all of the data in this memory, the user could determine whether a process control event caused a particular network alarm or vice versa.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention.